2airishuman
Contributor
Did you have a backup when diving solo, 2air?
What is right for me isn't necessarily right for anyone else. Here's what I do, at this point.
When I dive over a hard bottom that is less than 30' deep, with a rig I know I can swim up in the event of a BC rupture, with benign surface conditions, I don't use a redundant air source.
When I dive with a buddy, instructor, or divemaster who I trust, in good visibility, where bringing a redundant air source poses an unreasonable logistical burden, I don't use a redundant air source. This characterizes many of my tropical dives.
Otherwise, I bring a redundant air source. It can be either a twinset or a pony cylinder.